Merge branch 'netns'

Nicolas Dichtel says:

====================
netns: audit netdevice creation with IFLA_NET_NS_[PID|FD]

When one of these attributes is set, the netdevice is created into the netns
pointed by IFLA_NET_NS_[PID|FD] (see the call to rtnl_create_link() in
rtnl_newlink()). Let's call this netns the dest_net. After this creation, if the
newlink handler exists, it is called with a netns argument that points to the
netns where the netlink message has been received (called src_net in the code)
which is the link netns.
Hence, with one of these attributes, it's possible to create a x-netns
netdevice.

Here is the result of my code review:
- all ip tunnels (sit, ipip, ip6_tunnels, gre[tap][v6], ip_vti[6]) does not
  really allows to use this feature: the netdevice is created in the dest_net
  and the src_net is completely ignored in the newlink handler.
- VLAN properly handles this x-netns creation.
- bridge ignores src_net, which seems fine (NETIF_F_NETNS_LOCAL is set).
- CAIF subsystem is not clear for me (I don't know how it works), but it seems
  to wrongly use src_net. Patch #1 tries to fix this, but it was done only by
  code review (and only compile-tested), so please carefully review it. I may
  miss something.
- HSR subsystem uses src_net to parse IFLA_HSR_SLAVE[1|2], but the netdevice has
  the flag NETIF_F_NETNS_LOCAL, so the question is: does this netdevice really
  supports x-netns? If not, the newlink handler should use the dest_net instead
  of src_net, I can provide the patch.
- ieee802154 uses also src_net and does not have NETIF_F_NETNS_LOCAL. Same
  question: does this netdevice really supports x-netns?
- bonding ignores src_net and flag NETIF_F_NETNS_LOCAL is set, ie x-netns is not
  supported. Fine.
- CAN does not support rtnl/newlink, ok.
- ipvlan uses src_net and does not have NETIF_F_NETNS_LOCAL. After looking at
  the code, it seems that this drivers support x-netns. Am I right?
- macvlan/macvtap uses src_net and seems to have x-netns support.
- team ignores src_net and has the flag NETIF_F_NETNS_LOCAL, ie x-netns is not
  supported. Ok.
- veth uses src_net and have x-netns support ;-) Ok.
- VXLAN didn't properly handle this. The link netns (vxlan->net) is the src_net
  and not dest_net (see patch #2). Note that it was already possible to create a
  x-netns vxlan before the commit f01ec1c0 ("vxlan: add x-netns support")
  but the nedevice remains broken.

To summarize:
 - CAIF patch must be carefully reviewed
 - for HSR, ieee802154, ipvlan: is x-netns supported?
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/caif/caif_hsi.c

@@ -1415,7 +1415,6 @@ static int caif_hsi_newlink(struct net *src_net, struct net_device *dev,
 
 	cfhsi = netdev_priv(dev);
 	cfhsi_netlink_parms(data, cfhsi);
-	dev_net_set(cfhsi->ndev, src_net);
 
 	get_ops = symbol_get(cfhsi_get_ops);
 	if (!get_ops) {

drivers/net/vxlan.c

@@ -2432,10 +2432,10 @@ static void vxlan_sock_work(struct work_struct *work)
 	dev_put(vxlan->dev);
 }
 
-static int vxlan_newlink(struct net *net, struct net_device *dev,
+static int vxlan_newlink(struct net *src_net, struct net_device *dev,
 			 struct nlattr *tb[], struct nlattr *data[])
 {
-	struct vxlan_net *vn = net_generic(net, vxlan_net_id);
+	struct vxlan_net *vn = net_generic(src_net, vxlan_net_id);
 	struct vxlan_dev *vxlan = netdev_priv(dev);
 	struct vxlan_rdst *dst = &vxlan->default_dst;
 	__u32 vni;
@@ -2445,7 +2445,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
 	if (!data[IFLA_VXLAN_ID])
 		return -EINVAL;
 
-	vxlan->net = dev_net(dev);
+	vxlan->net = src_net;
 
 	vni = nla_get_u32(data[IFLA_VXLAN_ID]);
 	dst->remote_vni = vni;
@@ -2481,7 +2481,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
 	if (data[IFLA_VXLAN_LINK] &&
 	    (dst->remote_ifindex = nla_get_u32(data[IFLA_VXLAN_LINK]))) {
 		struct net_device *lowerdev
-			 = __dev_get_by_index(net, dst->remote_ifindex);
+			 = __dev_get_by_index(src_net, dst->remote_ifindex);
 
 		if (!lowerdev) {
 			pr_info("ifindex %d does not exist\n", dst->remote_ifindex);
@@ -2557,7 +2557,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
 	    nla_get_u8(data[IFLA_VXLAN_UDP_ZERO_CSUM6_RX]))
 		vxlan->flags |= VXLAN_F_UDP_ZERO_CSUM6_RX;
 
-	if (vxlan_find_vni(net, vni, use_ipv6 ? AF_INET6 : AF_INET,
+	if (vxlan_find_vni(src_net, vni, use_ipv6 ? AF_INET6 : AF_INET,
 			   vxlan->dst_port)) {
 		pr_info("duplicate VNI %u\n", vni);
 		return -EEXIST;

net/caif/chnl_net.c

@@ -470,7 +470,6 @@ static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 	ASSERT_RTNL();
 	caifdev = netdev_priv(dev);
 	caif_netlink_parms(data, &caifdev->conn_req);
-	dev_net_set(caifdev->netdev, src_net);
 
 	ret = register_netdevice(dev);
 	if (ret)